Grab-bucket hoist.



s. H.VL1BBY. GRAB BUCKET HOIST.

APPLICATION FILED SEPT.21, 19410. 1,01 9,500. Patented Mar. 5, 1912.

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1,019,500. 4 Patented Mar. 5, 1912. l

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GRAB BUCKET HOIST.. APPLICATION FILED SEPT. 21, 1910.

Patented Mar. 5, 1912.

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GRAB BUCKET HOIST. APPLICATION FILED` ssPTQ 21, 1910.

Patented Mar. 5, 1912.

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GRAB BUCKET HOIST.

APPLICATION FILED SEPT. 21, 1910.

1,01 9,500. Pand Mar. 5, 1912.

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UNITED STATES PATENT OFFICE.

HaTf-IBBY, 0F BLOOMFIELD, NEW JERSEY, ASSIGNOR T0 GENERAL ELECTRIC I COMPANY, A CORPORATION OF NEW YORK.

VGRABBUCKET HOIST.

Be it known that I, SAM H. LIBBY, a citizen of the United States, residing at Bloomfield, county of Essex, State of New Jersey, have invented certain new and useful hnprovements in Grab-Bucket Hoists,'of which the followingis a specification.'

This invention relates to electric hoistlng apparatus in which buckets of the cla-m Shell or orangepeel type are used to pick up and lift a load of loose material, and subse quently dump the saine at some desired spot.

The Iobject of the invention isto simplify the control apparatus and render the operation of the hoist convenient and reliable.

Hoists of this kind are provided with two ropes, one for closing and opening the jaws or valves of the bucket, commonly called the lacing rope, and the other for lifting and lowering the bucket, called the holding rope. In operating the hoist, the bucket, ywhich may be assumed to be open and resting on the pile of material, is first closed by pulling up on the lacing rope. Bot-h ropes are then wound up to lift the closed bucket and its contents. When it is desired to dump the bucket the lacing rope is slacked olf a certain amount. To lower the bucket again, both ropes are paid out at the same rate. y

My invention provides a simple arrangement of one or two electric motors, clutches, and a controller by means of which this cycle of operation can be easily effected, as hereinafter set forth and particularly pointed out in the claims.

In the accompanying drawings, Figure 1 is a diagrammatic representation of a grab bucket, two hoisting drums, a single motor geared thereto, and a controller' for-said motor; Fig. 2 is a series of diagrams of the circuit-s of said motor as varied by the operation of said controller; Fig. 3 shows dia grammatically an arrangement employing two motors; Fig. 4 is a series ot' diagrams showing some of the circuit changes in this arrangement, and Fig. 5 is a continuation of Fi .4.

Regerring irst to Figs. 1 and 2, the grab bucket- 1 of the clam shell type is provided with a holding rope 2 and a lacing rope 3, running respectively to drums 4 5 both of the Same size, which can be connected by the manually-operated clutches 6 7 with the Specification of Letters Patent.

Patented Mar. 5, 1912.

Application led September 21, 1910. Serial `No. 583,029.

shafts 8 9 suitably geared to the single elec tric motor 10, in such a manner that both drums will run at the same speed. An electromagnetic brake 11 is applied to the shaft of the motor, its releasing coil 12 being in series with t-he field coil 18 of the motor, which is of the usual series type. The controller 14 has ten running positions and an off position. In the position shown in Fig. 1 and in the diagram Fig. 2-O, the field coil and armature are opencircuited. The bucket is open`and resting on the pile of material to be hoisted. The operator now moves his controller to position 1 and closes the lacing clutch 7. The motor circuits, as

show n in Fig. 2-I, may be traced from the line 15 through linger 16, contact segments 26, 27, finger 18, resistance coils c d e, brake coil 1,2, field coil 13, finger 22, contacts 31, 32, finger 23, armature brushes 15, linger 24, contacts 33, 34, and finger 25 to the other side of the line. The controller is quickly turned through the next three positions II, III, IV, in o-rder to cut out all the resistance and accelerate the motor tol full speed. The instant the jaws of the bucket have been closed by the winding up of the lacing rope, the holding clutch 6 is closed and both ropes are wound up at full speed, hoisting the closed bucket. When it is at the required height, the controller is then turned to position V, open-circuiting the'motor again and letting the brake go on to hold the load suspended. To dump it, the lacing clutch 7 is opened, slacking oif the lacing rope and permitting the bucket to open. To lower cit-her the load or ythe empty bucket, the lacing clutch is closed and the controller is turned to the lowering position VI which cuts all the resistance into the motor circuit and re duces the current to such an extent that the weight of the full or empty bucket will overhaul the motor through the pull of the hold ing rope on its drum. The lacing drum,' being geared to the motor shaft, will pay out the lacing rope at the same speed as the holding rope, so that it cannot become too slack, nor on the other hand will it close the bucket if empty. The several lowering positions from VI to XI enable Pthe. motor to be lowered at any desired speed by varying the resistance in circuit. It will be observed t-hatthe first hoisting position (I) has less resistance in circuit than the first lowering position (VD. Consequently, this diifer- ,sition ence'in resistancev can adjusted to suit the conditions, so that a load which would be picked up on the first hoistingl position might be lowered on the iirst lowering p0- sition, or possibly on the second lowering polf the loadg'ets to dropping too rapidly, the resistance would be out out until the right speed has been obtained,4 at which times some of the points after the second lowering position would quite likely be used.

l'n Figs. 3, 4l and 5, l have shown a molditication in which two separate motors 40,147 are used7 geared respectively to the holding drum 48 and tlfe lacing drum L9 in such manner that bota drums rotate at the same speed. *fill he lacing drum is loose on its shaft and can be coupled thereto by a manual.

clutch 5G, but the holding drum is keyed :tast on its shaft so as to rotate whenever its motor runs.v Each' motor has a. brake 51 with a releasing magnet coil 52. .The motorsy are series wouinl,='and are both controlled by one controller 53, which hassevcn hoisting positions to VL'D and sixlowering positions to Kill), with an intermediate oit position (vill). Assume 'that the bucket is open and is resting on the pile of .material to be hoisted: rilhe operator closes the lacing clutch and moves--the controller vto positions l, lLlll, lV, which produce the connections shown in. Fig. 4f-l, llt, Hl, 1V, gradually cutting out the resistance coils 554i., The lacing motor runs up to 'ull speed and closes the bucket upon its load. The resistance in the circuit of the holding motor permits it to exert only suflicient torque to keep the holding' rope taut with-- out lifting the bucket out of the material. To hoist, Athe controller is turned, first to position V, which throws equal resistance upon both motor circuits, cutting out a part of that formerly in the holding motor circuit, and allowing said motor to lift the load. Positions Vi and VH cutI out all the resistance from both motor circuits and run the motors up to full speed to hoist the load. When lifted high enough the controller is turned another notch to VH, which opencircuits both motors and denergizes the releasing' magnets, so that the brakes can sustain the load. rlhe next position, 1X, cuts in both motors with all of both resistances 54, 55 in circuit. This weakens their torque to such an extent that the load will overhaul them, turning their armaturesL backward and permit-ting the closed bucket to be lowered. The next step, X, open-circuits the lacing motor and leaves the lowering of the bucket to be handled by the holding motor whose speed of overhauling,v can be regulated by cutting out more or less of its resistance 55, as provided for in steps'XI, XH, Xllll. rlfhebucket must be dumped before this by pulling open the clutchvO of the laci ,ing drum, because when the lacing motor is open circuited it becomes locked by ,its brake. ln lowering after opening said by the lacing rope without danger of closingl the bucket, but as soon as the bucket reaches the pile of material and the holding motor is stopped ,the lacing clutch should be closed to stop the drum and prevent the unreeling of too much rope. n

ln accordance with the provisions of the pat-ent statutes, l have described the principle of operation of my invention, to-

sider to represent the best embodiment thereof; but l desire ,to have it understood that the 4apparatus shown is only illustraing' bothy of said motors.,

2. ln a grab bucket hoist, the combination clutch for the lacing drum, a separate series wound electric motor geared to each drum, and a 'controller comprising suitable segments, fingerst and resistances and adapted lacing motor, then both motors at the same speed for hoisting, then throwing increased resistance into both ,motor circuits for' lowering the bucket. closed by overhauling both `resistance in the circuit of the holding motor.

In witness whereof, I have hereunto set my hand this 15th day of September, 1910.

SAM n. meer.

Witnesses i,

ROGER H. BU'r'rnRwoR'rH, ANNA S. MCMANIUS.

clutch, the lacing drum is easily overhauled gether with the apparatus which l now con-` tive, and that the invention can be carried y creased resistance into both motor circuits for lowering the bucket closed by overhaulwith the bucket andA the'holding and lacing ropes, of a separate drum for each rope, a

in itsv various positions to operate rst the oie said motors, and finally open-circuiting.. the lacing motor and lowering by control of y 

